Applying Fractions
When are we going to use this?
• Cooking – cutting a recipe in half or double it.
• Construction – using blueprints
Multiplying fractions
• 1. Make mixed numbers into improper fractions.
• 2. Multiply numerators
• 3. Multiply denominators
• 4. Simplify fractions if needed.
Example
• 1 x 3 = 3x1 = 3
5 8 5x8 40
2 1 x 5 = 7 x 5 = 7x5 = 35 = 1 8
3 9 3 9 3x9 27 27
What happens to the numerator when we multiply fractions?
• 3 x 3 = 3x3 = 9
4 5 = 4x5 20
The numerator became larger.
What happens to the denominator when we multiply fractions?
• 3 x 3 = 3x3 = 9
4 5 = 4x5 20
The denominator became larger.
What happens to the answer when we multiply fractions?
• 3 x 3 = 3x3 = 9
4 5 = 4x5 20
The answer became smaller than both of the original fractions.
Describe the effects of multiplication on fractions.
• Multiplying fractions actually creates a smaller fraction.